Android WebView JavaScript交互

 今天介绍一下，Android中Webview与JavaScript的交互，首先是在布局文件里添加webview控件：

<WebView
        android:id="@+id/webview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

  然后是在manifest里添加权限：

<uses-permission android:name="and

  要是webview能够与JavaScript交互，首先需要webview要启用JavaScript：

WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);

  然后创建JavaScript的接口：

public class WebAppInterface {
        Context mContext;

        /** Instantiate the interface and set the context */
        WebAppInterface(Context c) {
            mContext = c;
        }

        /** Show a toast from the web page */
        @JavascriptInterface
        public void showToast(String toast) {
            Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
        }
    }

  给webview添加JavaScript接口：

myWebView.addJavascriptInterface(new WebAppInterface(this), "Android");

  本地JavaScript文件：

<input type="button" value="Say hello" onClick="showAndroidToast('Hello Android!')" />

<script type="text/javascript">
    function showAndroidToast(toast) {
        Android.showToast(toast);
    }
</script>

  整个代码如下：

public class MainActivity extends Activity {
    private WebView myWebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myWebView = (WebView) findViewById(R.id.webview);
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        myWebView.addJavascriptInterface(new WebAppInterface(this), "Android");
        ProcessWebString();

    }

    public class WebAppInterface {
        Context mContext;

        /** Instantiate the interface and set the context */
        WebAppInterface(Context c) {
            mContext = c;
        }

        /** Show a toast from the web page */
        @JavascriptInterface
        public void showToast(String toast) {
            Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
        }
    }

    private void ProcessWebString() {
        // 加载 asset 文件
        String tpl = getFromAssets("web_tpl.html");
        myWebView.loadDataWithBaseURL(null, tpl, "text/html", "utf-8", null);
    }

    /*
     * 获取html文件
     */
    public String getFromAssets(String fileName) {
        try {
            InputStreamReader inputReader = new InputStreamReader(
                    getResources().getAssets().open(fileName));
            BufferedReader bufReader = new BufferedReader(inputReader);
            String line = "";
            String Result = "";
            while ((line = bufReader.readLine()) != null)
                Result += line;
            return Result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "";
    }

}

  运行效果：